aimen_mod.m

cognitive radio simulation

    clc
    close all
    clear all
    
    t = 0:0.00001:0.001;
    Fc1 = 1000;
    Fc2 = 2000;
    Fc3 = 3000;
    Fc4 = 4000;
    Fc5 = 5000;
    Fs = 12000;
    y1 = 1; y2 = 0; y3 = 0; y4 = 0; y5 = 0; Y = 0; y = 0;
    
    x1 = cos(2*pi*1000*t);
  
    in_p = input('\nDo you want to enter first primary user Y/N:  ','s');
   
    
    if(in_p == 'Y' | in_p == 'y')
        y1 = ammod(x1,Fc1,Fs);
        
    end
    
    in_p = input('Do you want to enter second primary user Y/N:  ','s');
    
    if(in_p == 'Y' | in_p == 'y')
        y2 = ammod(x1,Fc2,Fs);
    
    end
        
    in_p = input('Do you want to enter third primary user Y/N:  ','s');

    if(in_p == 'Y' | in_p == 'y')
        y3 = ammod(x1,Fc3,Fs);
       
    end

    in_p = input('Do you want to enter fourth primary user Y/N:  ','s');

    if(in_p == 'Y' | in_p == 'y')
        y4 = ammod(x1,Fc4,Fs);
    
    end

    in_p = input('Do you want to enter fifth primary user Y/N:  ','s');
    
    if(in_p == 'Y' | in_p == 'y')
        y5 = ammod(x1,Fc5,Fs);
        
    end
    
    y = y1 + y2 + y3 + y4 + y5;
    
while(1)
    
        Pxx = periodogram(y);
        Hpsd = dspdata.psd(Pxx,'Fs',Fs);
        plot(Hpsd);
    
        
  in_p = input('\nDo you want to enter another primary user Y/N:  ','s');
 
    if(in_p == 'Y' | in_p == 'y')
    
        
    
        
        chek1 = Pxx(25).*10000;
        chek2 = Pxx(46).*10000;
        chek3 = Pxx(62).*10000;
        chek4 = Pxx(89).*10000;
        chek5 = Pxx(105).*10000;
        
        if(chek1 < 8000)
            disp('Assigned to User 1 as it was not present.');
            y1 = ammod(x1,Fc1,Fs);
    

    elseif (chek2 < 8000)
            disp('Assigned to User 2 as it was not present.');
            y2 = ammod(x1,Fc2,Fs);
        
    
        elseif(chek3 < 8000)
            disp('Assigned to User 3 as it was not present.');
            y3 = ammod(x1,Fc3,Fs);
        
    
        elseif(chek4 < 8000)
            disp('Assigned to User 4 as it was not present.');
            y4 = ammod(x1,Fc4,Fs);
        

        elseif(chek5 < 8000)
            disp('Assigned to User 5 as it was not present.');
            y5 = ammod(x1,Fc5,Fs);
        else
            disp('all user slots in use. try again later,');

        end
        
        
        y = y1 + y2 + y3 + y4 + y5 ;
    end
end